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ca203e9985
This patch does 4 things, all of which interact and thus it woudln't be possible to commit them separately without causing either quality regressions or assertion failures. Fate comparison targets don't all reflect improvements in quality, yet listening tests show substantially improved quality and stability. 1. Increase SF range utilization. The spec requires SF delta values to be constrained within the range -60..60. The previous code was applying that range to the whole SF array and not only the deltas of consecutive values, because doing so requires smarter code: zeroing or otherwise skipping a band may invalidate lots of SF choices. This patch implements that logic to allow the coders to utilize the full dynamic range of scalefactors, increasing quality quite considerably, and fixing delta-SF-related assertion failures, since now the limitation is enforced rather than asserted. 2. PNS tweaks The previous modification makes big improvements in twoloop's efficiency, and every time that happens PNS logic needs to be tweaked accordingly to avoid it from stepping all over twoloop's decisions. This patch includes modifications of the sort. 3. Account for lowpass cutoff during PSY analysis The closer PSY's allocation is to final allocation the better the quality is, and given these modifications, twoloop is now very efficient at avoiding holes. Thus, to compute accurate thresholds, PSY needs to account for the lowpass applied implicitly during twoloop (by zeroing high bands). This patch makes twoloop set the cutoff in psymodel's context the first time it runs, and makes PSY account for it during threshold computation, making PE and threshold computations closer to the final allocation and thus achieving better subjective quality. 4. Tweaks to RC lambda tracking loop in relation to PNS Without this tweak some corner cases cause quality regressions. Basically, lambda needs to react faster to overall bitrate efficiency changes since now PNS can be quite successful in enforcing maximum bitrates, when PSY allocates too many bits to the lower bands, suppressing the signals RC logic uses to lower lambda in those cases and causing aggressive PNS. This tweak makes PNS much less aggressive, though it can still use some further tweaks. Also update MIPS specializations and adjust fuzz Also in lavc/mips/aacpsy_mips.h: remove trailing whitespace |
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| compat | ||
| doc | ||
| libavcodec | ||
| libavdevice | ||
| libavfilter | ||
| libavformat | ||
| libavresample | ||
| libavutil | ||
| libpostproc | ||
| libswresample | ||
| libswscale | ||
| presets | ||
| tests | ||
| tools | ||
| .gitattributes | ||
| .gitignore | ||
| .travis.yml | ||
| arch.mak | ||
| Changelog | ||
| cmdutils_common_opts.h | ||
| cmdutils_opencl.c | ||
| cmdutils.c | ||
| cmdutils.h | ||
| common.mak | ||
| configure | ||
| COPYING.GPLv2 | ||
| COPYING.GPLv3 | ||
| COPYING.LGPLv2.1 | ||
| COPYING.LGPLv3 | ||
| CREDITS | ||
| ffmpeg_dxva2.c | ||
| ffmpeg_filter.c | ||
| ffmpeg_opt.c | ||
| ffmpeg_qsv.c | ||
| ffmpeg_vdpau.c | ||
| ffmpeg_videotoolbox.c | ||
| ffmpeg.c | ||
| ffmpeg.h | ||
| ffplay.c | ||
| ffprobe.c | ||
| ffserver_config.c | ||
| ffserver_config.h | ||
| ffserver.c | ||
| INSTALL.md | ||
| library.mak | ||
| LICENSE.md | ||
| MAINTAINERS | ||
| Makefile | ||
| README.md | ||
| RELEASE | ||
| version.sh | ||
FFmpeg README
FFmpeg is a collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata.
Libraries
libavcodecprovides implementation of a wider range of codecs.libavformatimplements streaming protocols, container formats and basic I/O access.libavutilincludes hashers, decompressors and miscellaneous utility functions.libavfilterprovides a mean to alter decoded Audio and Video through chain of filters.libavdeviceprovides an abstraction to access capture and playback devices.libswresampleimplements audio mixing and resampling routines.libswscaleimplements color conversion and scaling routines.
Tools
- ffmpeg is a command line toolbox to manipulate, convert and stream multimedia content.
- ffplay is a minimalistic multimedia player.
- ffprobe is a simple analysis tool to inspect multimedia content.
- ffserver is a multimedia streaming server for live broadcasts.
- Additional small tools such as
aviocat,ismindexandqt-faststart.
Documentation
The offline documentation is available in the doc/ directory.
The online documentation is available in the main website and in the wiki.
Examples
Coding examples are available in the doc/examples directory.
License
FFmpeg codebase is mainly LGPL-licensed with optional components licensed under GPL. Please refer to the LICENSE file for detailed information.
Contributing
Patches should be submitted to the ffmpeg-devel mailing list using
git format-patch or git send-email. Github pull requests should be
avoided because they are not part of our review process. Few developers
follow pull requests so they will likely be ignored.